package com.chhuang.utils.string;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * AES加解密工具
 * @author 程秀超
 * @date 2013-4-2
 *
 */
public class DigestUtil {
	
	private static final String encryptPwd = "synergyinfo";

	/**
	 * 加密
	 * 
	 * @param content
	 *            需要加密的内容
	 * @param password
	 *            加密密码
	 * @return
	 */
	public static byte[] encrypt(String content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			kgen.init(128, new SecureRandom(password.getBytes()));
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");// 创建密码器
			byte[] byteContent = content.getBytes(StringEncoding.CHARSET_UTF8);
			cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
			byte[] result = cipher.doFinal(byteContent);
			return result; // 加密
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 解密
	 * 
	 * @param content
	 *            待解密内容
	 * @param password
	 *            解密密钥
	 * @return
	 */
	public static byte[] decrypt(byte[] content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			kgen.init(128, new SecureRandom(password.getBytes()));
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");// 创建密码器
			cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
			byte[] result = cipher.doFinal(content);
			return result; // 加密
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 将二进制转换成16进制
	 * 
	 * @param buf
	 * @return
	 */
	public static String parseByte2HexStr(byte buf[]) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < buf.length; i++) {
			String hex = Integer.toHexString(buf[i] & 0xFF);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			sb.append(hex.toUpperCase());
		}
		return sb.toString();
	}

	/**
	 * 将16进制转换为二进制
	 * 
	 * @param hexStr
	 * @return
	 */
	public static byte[] parseHexStr2Byte(String hexStr) {
		if (hexStr.length() < 1)
			return null;
		byte[] result = new byte[hexStr.length() / 2];
		for (int i = 0; i < hexStr.length() / 2; i++) {
			int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
			int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2),
					16);
			result[i] = (byte) (high * 16 + low);
		}
		return result;
	}
	
	public static byte[] getMainKey(String mainKeyEncrypt) {
		String mainKey = decrypt(mainKeyEncrypt);
		
		String[] hexs = mainKey.split(",");
		
		StringBuffer sb = new StringBuffer();
		for(int i = 0; i < hexs.length; i++) {
			hexs[i] = hexs[i].substring(2, 4);
			sb.append(hexs[i]);
		}
		
		byte[] bytes = hexStringToBytes(sb.toString());
		
		return bytes;
	}
	
	public static byte[] hexStringToBytes(String hexString) {  
	    if (hexString == null || hexString.equals("")) {  
	        return null;  
	    }  
	    hexString = hexString.toUpperCase();  
	    int length = hexString.length() / 2;  
	    char[] hexChars = hexString.toCharArray();  
	    byte[] d = new byte[length];  
	    for (int i = 0; i < length; i++) {  
	        int pos = i * 2;  
	        d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));  
	    }  
	    return d;  
	}  
	
	private static byte charToByte(char c) {  
	    return (byte) "0123456789ABCDEF".indexOf(c);  
	}
	
	/**
	 * 使用默认密码加密
	 * @param content
	 * @return
	 */
	public static String encyptStr(String content) {
		byte[] encryptResult = encrypt(content, encryptPwd);
		String encryptResultStr = parseByte2HexStr(encryptResult);
		
		return encryptResultStr;
	}
	
	/**
	 * 使用默认密码解密
	 * @param encryptStr
	 * @return
	 */
	public static String decrypt(String encryptStr) {
		byte[] decryptFrom = parseHexStr2Byte(encryptStr);
		byte[] decryptResult = decrypt(decryptFrom, encryptPwd);
		
		return new String(decryptResult);
	}

//	public static void main(String[] args) {
//		String content = "0x0E,0xB4,0x95,0x8C,0xB7,0xD6,0xC4,0xCF,0x2F,0xCB,0x5D,0xF3,0xF3,0xD1,0x94,0x5B,0xF8,0x20,0x14,0x52,0x8B,0x78,0x30,0xD3,0xF7,0x0F,0x0F,0x6C,0x74,0x41,0x84,0x36,0x01,0x29,0x35";
//		String content = "ab";
//		// 加密
//		System.out.println("加密前：" + content);
//		String enc = encyptStr(content);
//		System.out.println("加密后：" + enc);
//		// 解密
//		decrypt(enc);
//	}

}
